For high-frequency transmission, a multi-core cable in which plural coaxial cables are collected inside a sheath member having flexibility is known (for example, see JP-2001-023456-A).
Such multi-core cable may be used in medical devices such as a catheter, an endoscope or a probe cable for ultrasonograph, and thus, further reduction in diameter thereof is desired in order to improve workability or handleability of the cable to thereby reduce a stress for a patient to be treated with the endoscope etc.